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yanglbme
2019-08-21 10:10:08 +08:00
parent abc0d365de
commit 69ddc9fc52
101 changed files with 3154 additions and 2984 deletions
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110
Search/ternary_search.cpp
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@@ -25,7 +25,7 @@ using namespace std;
#define MAX 10000000
int N = 21;
int A[MAX] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,2,3,4,10};
int A[MAX] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 4, 10};
/*
* get_input function is to receive input from standard IO
@@ -35,82 +35,94 @@ void get_input()
// TODO: Get input from STDIO or write input to memory as done above.
}
/*
* This is the iterative method of the ternary search which returns the index of the element.
*/
int it_ternary_search(int left, int right, int A[],int target)
int it_ternary_search(int left, int right, int A[], int target)
{
while (1)
{
if (left < right)
{
if(left<right)
{
if(right-left < absolutePrecision)
{
for(int i=left;i<=right;i++)
if(A[i] == target) return i;
return -1;
}
int oneThird = (left+right)/3+1;
int twoThird = (left+right)*2/3+1;
if(A[oneThird] == target) return oneThird;
else if(A[twoThird] == target) return twoThird;
else if(target > A[twoThird]) left = twoThird+1;
else if(target < A[oneThird]) right = oneThird-1;
else left = oneThird+1, right = twoThird-1;
}
else return -1;
if (right - left < absolutePrecision)
{
for (int i = left; i <= right; i++)
if (A[i] == target)
return i;
return -1;
}
int oneThird = (left + right) / 3 + 1;
int twoThird = (left + right) * 2 / 3 + 1;
if (A[oneThird] == target)
return oneThird;
else if (A[twoThird] == target)
return twoThird;
else if (target > A[twoThird])
left = twoThird + 1;
else if (target < A[oneThird])
right = oneThird - 1;
else
left = oneThird + 1, right = twoThird - 1;
}
else
return -1;
}
}
/*
* This is the recursive method of the ternary search which returns the index of the element.
*/
int rec_ternary_search(int left, int right, int A[],int target)
int rec_ternary_search(int left, int right, int A[], int target)
{
if(left<right)
if (left < right)
{
if (right - left < absolutePrecision)
{
if(right-left < absolutePrecision)
{
for(int i=left;i<=right;i++)
if(A[i] == target) return i;
return -1;
}
int oneThird = (left+right)/3+1;
int twoThird = (left+right)*2/3+1;
for (int i = left; i <= right; i++)
if (A[i] == target)
return i;
if(A[oneThird] == target) return oneThird;
if(A[twoThird] == target) return twoThird;
if(target < A[oneThird]) return rec_ternary_search(left, oneThird-1, A, target);
if(target > A[twoThird]) return rec_ternary_search(twoThird+1, right, A, target);
return rec_ternary_search(oneThird+1, twoThird-1, A, target);
return -1;
}
else return -1;
int oneThird = (left + right) / 3 + 1;
int twoThird = (left + right) * 2 / 3 + 1;
if (A[oneThird] == target)
return oneThird;
if (A[twoThird] == target)
return twoThird;
if (target < A[oneThird])
return rec_ternary_search(left, oneThird - 1, A, target);
if (target > A[twoThird])
return rec_ternary_search(twoThird + 1, right, A, target);
return rec_ternary_search(oneThird + 1, twoThird - 1, A, target);
}
else
return -1;
}
/*
* ternary_search is a template function
* You could either use it_ternary_search or rec_ternary_search according to preference.
*/
void ternary_search(int N,int A[],int target)
void ternary_search(int N, int A[], int target)
{
cout << it_ternary_search(0,N-1,A,target) << '\t';
cout << rec_ternary_search(0,N-1,A,target) << '\t';
cout << it_ternary_search(0, N - 1, A, target) << '\t';
cout << rec_ternary_search(0, N - 1, A, target) << '\t';
cout << '\n';
}
int main()
{
get_input();
ternary_search(N,A,_target);
ternary_search(N, A, _target);
return 0;
}